"Tracks Across the Sky: 
Computational Astronomy 101"

David Nitz

St. Olaf Physics Department

 The autumnal equinox will occur in the week following this colloquium.  When will the sun rise that morning?  Where will it be at noon?  While “about 6AM (standard time)” and “45 degrees above the southern horizon” are good common sense responses to these questions, when we pay a little closer attention some interesting patterns – some familiar and some perhaps not so familiar - are seen to emerge.  This general-audience talk will employ 3-D plots and animations generated with Mathcad to help explore daily and seasonal phenomena of the changing sky, including asymmetries of sunrise and sunset, analemmas, zodiacal light, and other consequences of the fact that we view the sky from a tilted and spinning frame of reference.